My in-laws give us eggs all the time and I have noticed something funny going on with their eggs. IT's pretty subtle, but the shells are getting a little crumbly or brittle. They aren't soft, but I often have to pick out shells now because they don't hold up. The chickens eat scratch grains but they are free-range and they get tons of bugs and other yummy stuff in the hay fields. They have been on this diet for awhile so I don't think it's from that. They are sex-links that are going on their 3rd year, so I am thinking that this is just a sign of the egg quality deteriorating. Yes? no? Any ideas?